Microscope illuminator for both transmitted and vertical microscopy

ABSTRACT

A microscope illumination system provides light for both transmitted and vertical microscopy techniques. A transmitted light illuminator comprises a collector lens system, a zoom lens system, and a collimator lens system which direct the light from a source to the microscope condenser. The vertical illumination system utilizes the same light source and comprises a collimator lens system, a relay lens system, and a collector lens system which provides the light directed into the rear of the microscope objective by a beam splitter.

BACKGROUND OF THE INVENTION

This invention relates to a microscope illumination system, and more particularly, to an illumination system capable of providing light for transmitted as well as vertical microscopy techniques utilizing the Kohler method of illumination.

It is an object of the present invention to provide Kohler illumination for standard 4X through 100X objectives.

It is a further object of the present invention to provide transmitted light illumination using objectives of 4X to 100X without using special lenses.

It is a still further object of the present invention to provide an illumination system for vertical or transmitted light having lateral color-free imaging of the field iris.

It is another object of the present invention to provide Kohler illumination in the vertical light mode for standard 10X through 100X objectives.

It is still another object of the present invention to provide Kohler illumination in either the vertical or transmitted light modes of a microscope having up to a 24mm field.

Prior art illumination systems frequently required the use of additional lenses commonly referred to as "throw-in" lenses in order to accommodate transmitted light objectives from 4X to 100X. Also, prior art illumination systems for microscopes intended to be used with either vertical or transmitted light illumination, usually required separate sources of illumination.

BRIEF DESCRIPTION OF THE INVENTION AND DRAWINGS

The present invention avoids the use of throw-in lenses in transmitted light Kohler illumination systems by using a special zoom unit which permits filling both the field iris as well as the back aperture diaphram of the condenser simultaneously throughout the required range of adjustment for objectives ranging from 4X to 100X. The zoom unit offers one advantage in providing most efficient use of the illumination source for each objective rather than compromising on each of a plurality of objectives. Also, it is possible to use the illumination system of the present invention in both the transmitted light and vertical light modes simultaneously since each mode uses a different side of the filament.

FIG. 1 is an optical diagram of both the transmitted and vertical illumination systems viewed transverse to the optical axis thereof;

FIG. 2 is an optical diagram of the transmitted light portion of the illumination system in detail;

FIG. 3 is an optical diagram of an alternate collector lens system; and

FIG. 4 is an optical diagram of the vertical light portion of the illumination system.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a transmitted light system T collects light from filament 1 in a collector lens system X, which is then directed along an optical axis to zoom system XI. The light continues along the optical axis through field iris 2, through collimating system XII to the back aperture 3 of condenser 4 to object O. An aperture diaphram is usually positioned in the condenser back aperture 3 to permit the microscopist to adjust the intensity of illumination. Field iris 2 is used by the microscopist to adjust the area illuminated to suit a chosen objective. It is usually desirable to use a deflector 5 in order to reduce the size of a microscope base which would otherwise be required.

The vertical illumination portion V has a collector lens system XIII which collects light from the back of filament 1 and directs the same along an optical axis to relay lens system XIV, through aperture diaphram 6 and field iris 7 to collimator XV, which provides the light for the microscope objective 8 utilizing beam splitter 9. It is usually desirable to utilize a prism 10 and beam deflector 11 in order to utilize filament 1 instead or requiring an additional light source.

Referring to FIG. 2, collector X comprises a concavo-convex positive singlet 20, and a double convex positive singlet 21. The rearmost surface of singlet 21 is aspheric. Zoom system XI has a convex-plano positive singlet 22, and a plano-convex positive singlet 23. The collimator lens system XII comprises a double convex positive doublet 24, and a double convex positive singlet 25. With respect to lens parameters of the transmitted light illumination system, the axial thicknesses of successive lens elements are designated T1 to T7, and the axial spaces from the filament plane FO are designated S1 to S8. The successive lens radii are designated R1 to R13, wherein the minus sign (-) applies to surfaces whose center of curvature lies on the filament side of their vertices. The refraction indices and Abbe numbers of the glasses are designated ND(1) to ND(7) and ν(1) to ν(7), respectively.

Since the numerical aperture in size of the light in the object O is directly proportional to the focal length F, in millimeters, of condenser 4, the lens parameters in the following Table I are a function of F, which can typically vary from 9 to 12mm.

                                      TABLE I                                      __________________________________________________________________________                                  Index of Abbe                                     Lens                                                                               Radius (R)                                                                              Thickness (T)                                                                         Spacing (S)                                                                             Refraction (ND)                                                                         No. (ν)                               __________________________________________________________________________                         S.sub.1 =0.64633F                                              R.sub.1 =-3.38335F                                                         20           T.sub.1 =0.46536F                                                                              ND.sub.1 =1.523                                                                         ν.sub.1 =58.60                            R.sub.2 =-0.82730F                                                                             S.sub.2 =0.02585F                                              R.sub.3 =2.23395F                                                          21           T.sub.2 =0.62048F                                                                              ND.sub.2 =1.523                                                                         ν.sub.2 =58.60                            R.sub.4 =-0.99343F                                                                             S.sub.3 =1.5253F(4X)                                                             3.0765F(10X)                                                                   5.5584F(100X)                                                R.sub.5 =1.3940F                                                           22           T.sub.3 =0.41365F                                                                              ND.sub.3 =1.523                                                                         ν.sub.3 =58.60                            R.sub.6 =∞                                                                               S.sub.4 =0.72389F                                              R.sub.7 =∞                                                           23           T.sub.4 =0.41365F                                                                              ND.sub.4 =1.523                                                                         ν.sub.4 =58.60                            R.sub.8 =-1.6546F                                                                              S.sub.5 =5.8169F(4X)                                                             4.2658F(10X)                                                                   1.7839F(100X)                                                                S.sub.6 =1.03413F                                              R.sub.9 =10.8635F                                                                       T.sub.5 =0.77559F                                                                              ND.sub.5 =1.786                                                                         ν.sub.5 =25.52                        24  R.sub.10 =3.9555F                                                                       T.sub.6 =2.06825F                                                                              ND.sub.6 =1.588                                                                         ν.sub.6 =61.19                            R.sub.11 =-5.01551F                                                                            S.sub.7 =5.37746F                                              R.sub.12 =5.14478F                                                         25           T.sub.7 =1.24095F                                                                              ND.sub.7 =1.498                                                                         ν.sub.7 =66.94                            R.sub.13 =-24.8263F                                                                            S.sub.8 =6.72182                                           __________________________________________________________________________

Wherein F is in millimeters.

The back surface of singlet 21 with radius R₄, is an axially symmetrical aspheric surface with Z axis of revolution. The value of Z, for any given value of x and y, is defined by the equation:

    Z = cp.sup.2 / [1 +√ 1 - (k + 1)c.sup.2 p.sup.2 ] + dp.sup.4 + ep.sup.6 + fp.sup.8 + gp.sup.10

wherein:

d = 0.181924 × 10⁻³

e = -0.361616 × 10⁻⁵

f = 0.943675 × 10⁻⁷

g = -0.743223 × 10⁻⁹

p² = x² + y²

c = 1/R₄ and

k = 1.0

The mathematical support for this formula and explanation may be found in the Military Standard Handbook, MIL-HBDK-141 (50CT62), Sec. 5.5.1, Page 5-13 to 5-21.

Numerically stated, the preferred embodiment of the invention when the condenser has a focal length of 9.67mm, has the following relationship.

                  TABLE II                                                         ______________________________________                                         Lens  Radius (R)   Thickness (T)                                                                              Spacing (S)                                     ______________________________________                                                                        S.sub.1 =6.25                                         R.sub.1 =-32.717                                                         20                 T.sub.1 =4.500                                                    R.sub.2 =-8.000                                                                                         S.sub.2 =0.25                                         R.sub.3 =21.603                                                          21                 T.sub.2 =6.000                                                    R.sub.4 =-9.6065*                                                                                       S.sub.3 =14.75 (4X)                                                              29.75 (10X)                                                                    53.75 (100X)                                        R.sub.5 =13.480                                                          22                 T.sub.3 =4.000                                                    R.sub.6 =∞                                                                                        S.sub.4 =7.000                                        R.sub.7 =∞                                                         23                 T.sub.4 =4.000                                                    R.sub.8 =-16.000                                                                                        S.sub.5 =56.25 (4X)                                                              41.25 (10X)                                                                    17.25 (100X)                                                                 S.sub.6 =10.000                                       R.sub.9 =105.050                                                                            T.sub.5 =7.500                                              24    R.sub.10 =38.250                                                                            T.sub.6 =20.000                                                   R.sub.11 =-48.500                                                                                       S.sub.7 =52.000                                       R.sub.12 =49.750                                                         25                 T.sub.7 =12.000                                                   R.sub.13 =-240.070                                                                                      S.sub.8 =65.000                                 ______________________________________                                          *A conic coefficient and four aspheric deformation coefficients above.   

Referring to FIG. 3, alternate collector XA has a plano-convex positive singlet 26 as the first element. As the second element, the collector has a plano-convex positive singlet 27, and the last element is a double convex positive singlet 28. The rearmost surface of 27 and foremost surface of 28 are aspheric surfaces.

The magnification of collector groups X and XA is substantially the same (3X); however, collector group XA has a higher numerical aperture providing a larger filament image at back aperture plane 3 for a given field size at object plane O. With respect to lens parameters of the transmitted light illumination system, the axial thicknesses of successive lens elements are designated T101 to T103, and the axial spaces from the filament plane FO are designated S100 to S103. The successive lens radii are designated R101 to R106, wherein the minus sign (-) applies to surfaces whose center of curvature lies on the filament side of their vertices. The refraction indices and Abbe numbers of the glasses are designated ND(101) to ND(103) and ν (101) to ν (103), respectively.

                                      TABLE III                                    __________________________________________________________________________                                  Index of Abbe                                     Lens                                                                               Radius (R)                                                                              Thickness (T)                                                                         Spacing (S)                                                                             Refraction (ND)                                                                         No. (ν)                               __________________________________________________________________________                         S.sub.100 =0.5171F                                             R.sub.101 =∞                                                         26           T.sub.101 =0.5171F                                                                             ND.sub.101 =1.523                                                                       ν.sub.101 =58.60                          R.sub.102 =-0.9486F                                                                            S.sub.101 =0.0103F                                             R.sub.103 =∞                                                         27           T.sub.102 =0.5688F                                                                             ND.sub.102 =1.523                                                                       ν.sub.102 =58.60                          R.sub.104 =-1.15669F*                                                                          S.sub.102 =0.0103F                                             R.sub.105 =1.61446F**                                                      28           T.sub.103 =0.5688F                                                                             ND.sub.103 =1.523                                                                       ν.sub.103 =58.60                          R.sub.106 =-12.7564F                                                                           S.sub.103 =1.0910F(4X)                                                           2.6422F(10X)                                                                   5.1241F(100X)                                            __________________________________________________________________________      *Associated with R.sub.104 is a conic coefficient k= -0.99341 and four         aspheric deformation coefficients:                                             d = -0.50246 × 10.sup.-4                                                 e = -0.43451 × 10.sup.-5                                                 f = 0.11169 ×  10.sup.-6                                                 g = -0.57450 × 10.sup.-9                                                 **Associated with R.sub.105 is a conic coefficient k= -0.9817 and four         aspheric deformation coefficients:                                             d = -0.59858 × 10.sup.-4                                                 e = -0.44852 × 10.sup.-5                                                 f = 0.10981 × 10.sup.-6                                                  g = -0.60834 × 10.sup.-9                                           

A preferred embodiment of the alternate collector system using a condenser focal length of 9.67mm has the following specific values.

                  TABLE IV                                                         ______________________________________                                         Lens  Radius (R)   Thickness (T)                                                                              Spacing (S)                                     ______________________________________                                                                        S.sub.100 =5.00                                       R.sub.101 =∞                                                       26                 T.sub.101 =5.00                                                   R.sub.102 =-9.173                                                                                       S.sub.101 =0.100                                      R.sub.103 =∞                                                       27                 T.sub.102 =5.50                                                   R.sub.104 =-11.185*                                                                                     S.sub.102 =0.100                                      R.sub.105 =15.612**                                                      28                 T.sub.103 =5.50                                                   R.sub.106 =-123.354                                                                                     S.sub.103 =10.550 (4X)                                                           25.550 (10X)                                                                   49.550 (100X)                                 ______________________________________                                          *Coefficients appear above in Table III.                                       **Coefficients appear above in Table III.                                

The vertical illumination portion of the illumination system is more clearly shown in FIG. 4. Light from the backside of filament 1 is preferably deflected by prism 10 to collector XIII, which directs the light through relay system XIV to collimator XV, thence to beam splitter 9 and objective 8. Collector lens system XIII has, as the first element, a plano-convex positive singlet 29, and a plano-convex positive singlet 30. The relay lens system contains a double convex positive singlet 31, and a convex-Plano positive singlet 32, which provides a magnified image of filament 1 to aperture diaphram 12.

After imaging the filament at aperture diaphram 12, the light passes through field iris 13 to collimator 33. Collimating lens 33 is a double convex positive doublet which re-images the filament near the back image plane (shoulder of objective 8) and an image of field iris 13 substantially at infinity. Prism 10 and deflector 11 in conjunction with beam splitter 9, are used to fold the optical system to minimize space and provide a convenient optical path for association with a microscope.

With respect to lens parameters of the transmitted light illumination system, the axial thicknesses of successive lens elements are designated T201 to T207, and the axial spaces from the filament plane FO are designated S201 to S209. The successive lens radii are designated R201 to R211, wherein the minus sign(-) applies to surfaces whose center of curvature lies on the filament side of their vertices. The refraction indices and Abbe numbers of the glasses are designated ND(201) to ND(207) and ν(201) and ν (207), respectively.

                                      TABLE V                                      __________________________________________________________________________                                  Index of Abbe                                     Lens                                                                               Radius (R)                                                                              Thickness (T)                                                                         Spacing (S)                                                                             Refraction (ND)                                                                         No. (ν)                               __________________________________________________________________________                         S.sub.201 =0.56880                                                      T.sub.201 =1.2410Q                                                                             ND.sub.201 =1.69963                                                                     ν.sub.201 =34.67                                          S.sub.202 =0.0000Q                                             R.sub.201 =∞                                                         29           T.sub.202 =0.2585Q                                                                             ND.sub.202 =1.58904                                                                     ν.sub.202 =61.23                          R.sub.202 =-1.3005Q                                                                            S.sub.203 =1.2410Q                                             R.sub.203 =∞                                                         30           T.sub.203 =0.2585Q                                                                             ND.sub.203 =1.58904                                                                     ν.sub.203 =61.23                          R.sub.204 =-3.3739Q                                                                            S.sub.204 =14.5605Q                                            R.sub.205 =11.2289Q                                                        31           T.sub.204 =0.5171Q                                                                             ND.sub.204 =1.52300                                                                     ν.sub.204 =58.60                          R.sub.206 =-11.2289Q                                                                           S.sub.205 =9.7248Q                                             R.sub.207 =4.0384Q                                                         32           T.sub.205 =0.3619Q                                                                             ND.sub.205 =1.52300                                                                     ν.sub.205 =58.60                          R.sub.208 =∞                                                                             S.sub.206 =0.5336Q                                                             S.sub.207 =5.5843Q                                                             S.sub.208 =4.7053Q                                             R.sub.209 =7.8283Q                                                                      T.sub.206 =0.2585Q                                                                             ND.sub.206 =1.78600                                                                     ν.sub.206 =25.52                      33  R.sub.210 =4.0384Q                                                                      T.sub.207 =0.5171Q                                                                             ND.sub.207 =1.58904                                                                     ν.sub.207 =61.23                          R.sub.211 =-4.0384Q                                                                            S.sub.209 =9.2036Q                                         __________________________________________________________________________

Wherein Q is equal to 9 to 15mm.

A preferred embodiment of the vertical illumination system wherein Q is equal to 9.67mm is given by the following values.

                  TABLE VI                                                         ______________________________________                                         Lens  Radius (R)   Thickness (T)                                                                              Spacing (S)                                     ______________________________________                                                                        S.sub.201 =5.50                                                    T.sub.201 =12.00                                                                           S.sub.202 =0.00                                       R.sub.201 =∞                                                       29                 T.sub.202 =2.50                                                   R.sub.202 =-12.576                                                                                      S.sub.203 =12.00                                      R.sub.203 =∞                                                       30                 T.sub.203 =2.50                                                   R.sub.204 =-32.6255                                                                                     S.sub.204 =140.80                                     R.sub.205 =108.583                                                       31                 T.sub.204 =5.00                                                   R.sub.206 =-108.583                                                                                     S.sub.205 =94.04                                      R.sub.207 =39.051                                                        32                 T.sub.205 =3.50                                                   R.sub.208 =∞                                                                                      S.sub.206 =5.16                                                                S.sub.207 =54.00                                                               S.sub.208 =45.50                                      R.sub.209 =75.700                                                                           T.sub.206 =2.50                                             33    R.sub.210 =39.051                                                                           T.sub.207 =5.00                                                   R.sub.211 =-39.051                                                                                      S.sub.209 =89.00                                ______________________________________                                    

In the foregoing designs, particularly in the specific embodiments, a filament size of at least 2mm × 1mm is necessary to assure that the image of the filament extends entirely across the opening defined by the aperture diaphram 6 and/or 12. 

What is claimed is:
 1. In a transmitted light microscope illumination system having a light source, a collecting lens system, a field diaphragm, a collimating lens system, and a condenser with a back aperture diaphragm all in alignment and in sequence along an optical axis, the improvement comprising a zoom lens system, between said collecting lens system and said field diaphragm, said zoom system consisting of first and second lens elements movable along said axis in unison, said first lens element being a convex-plano positive singlet and said second lens element being a plano-convex positive singlet and said first and second lens elements having adjacent plano surfaces.
 2. The improvement of claim 1 wherein the parameters of said first and second lens elements are:

    __________________________________________________________________________                                  Index of Abbe                                     Lens                                                                               Radius (R)                                                                              Thickness (T)                                                                         Spacing (S)                                                                             Refraction (ND)                                                                         No. (ν)                               __________________________________________________________________________         R.sub.5 =1.3940F                                                           22           T.sub.3 =0.41365F                                                                              ND.sub.3 =1.523                                                                         ν.sub.3 =58.60                            R.sub.6 =∞                                                                               S.sub.4 =0.72389F                                              R.sub.7 =∞                                                           23           T.sub.4 =0.41365F                                                                              ND.sub.4 =1.523                                                                         ν.sub.4 =58.60                            R.sub.8 =-1.6546                                                           __________________________________________________________________________

wherein F is the focal length of the condenser in millimeters and refractive indices are Abbe numbers are absolute values.
 3. The improvement of claim 2 wherein F is 9.67mm.
 4. An illumination system for transmitted light microscopy comprising, in alignment and sequence along an optical axis, a light source, a collector lens system, a zoom lens system, a field diaphragm, a collimator lens system, and a condenser having a focal length F, said zoom lens system including convex-plano positive singlet (22) and a plano-convex positive singlet (23), said first and second elements being movable in unison along said optical axis, said collimator lens system having a double convex positive doublet (24) and a double convex positive singlet (25). being defined by the following relationship:

    __________________________________________________________________________                                  Index of Abbe                                     Lens                                                                               Radius (R)                                                                              Thickness (T)                                                                         Spacing (S)                                                                             Refraction (ND)                                                                         No. (ν)                               __________________________________________________________________________         R.sub.5 =1.3940F                                                           22           T.sub.3 =0.41365F                                                                              ND.sub.3 =1.523                                                                         ν.sub.3 =58.60                            R.sub.6 =∞                                                                               S.sub.4 =0.72389F                                              R.sub.7 =∞                                                           23           T.sub.4 =0.41365F                                                                              ND.sub.4 =1.523                                                                         ν.sub.4 =58.60                            R.sub.8 =-1.6546F                                                                              S.sub.5 =5.8169F(4X)                                                             4.2658F(10X)                                                                   1.7839F(100X)                                                                S.sub.6 =1.03413F                                              R.sub.9 =10.8635F                                                                       T.sub.5 =0.77559F                                                                              ND.sub.5 =1.786                                                                         ν.sub.5 =25.52                        24  R.sub.10 =3.9555F                                                                       T.sub.6 =2.06825F                                                                              ND.sub.6 =1.588                                                                         ν.sub.6 =61.19                            R.sub.11 =-5.01551F                                                                            S.sub.7 =5.37746F                                              R.sub.12 =5.14478F                                                         25           T.sub.7 =1.24095F                                                                              ND.sub.7 =1.498                                                                         ν.sub.7 =66.94                            R.sub.13 =-24.8263F                                                                            S.sub.8 =6.72182F                                          __________________________________________________________________________

Wherein F is in millimeters.
 5. The illumination system according to claim 4 wherein F is 9.67mm.
 6. The illumination system according to claim 4 wherein the collector lens system has a concavo-convex positive singlet (20) and a double convex positive singlet (21), said singlet (21) having an axially aspheric rear surface, and are defined by the following parameters:

    __________________________________________________________________________                                  Index of Abbe                                     Lens                                                                               Radius (R)                                                                              Thickness (T)                                                                         Spacing (S)                                                                             Refraction (ND)                                                                         No. (ν)                               __________________________________________________________________________                         S.sub.1 =0.64633F                                              R.sub.1 =-3.38335F                                                         20           T.sub.1 =0.46536F                                                                              ND.sub.1 =1.523                                                                         ν.sub.1 =58.60                            R.sub.2 =-0.82730F                                                                             S.sub.2 =0.02585F                                              R.sub.3 =2.23395F                                                          21           T.sub.2 =0.62048F                                                                              ND.sub.2 =1.523                                                                         ν.sub.2 =58.60                            R.sub.4 =-0.99343F                                                         __________________________________________________________________________

wherein R₄ has the following coefficients of asphericity: k = -1.0 d = 0.181924 × 10⁻³ e = -0.361616 × 10⁻⁵ f = 0.943675 × 10⁻⁷ g = -0.743223 × 10⁻⁹ and asphericity Z for any given value of x and y is defined by the equation

    Z = cp.sup.2 / [1 +√1 - (k + 1)c.sup.2 p.sup.2 ] + dp.sup.4 ep.sup.6 + fp.sup.8  + gp.sup.10

where c =1/R₄ and p² = x² + y².
 7. The illumination system according to claim 6 wherein F is 9.67mm.
 8. The illumination system according to claim 4 wherein the collector lens system has a plano-convex positive singlet (26), and a plano-convex positive singlet (27) and a double convex positive singlet (28), said singlet (27) having an axially aspheric rear surface, said singlet (28) having an axially aspheric front surface and are defined by the following parameters:

    __________________________________________________________________________                                  Index of Abbe                                     Lens                                                                               Radius (R)                                                                              Thickness (T)                                                                         Spacing (S)                                                                             Refraction (ND)                                                                         No. (ν)                               __________________________________________________________________________                         S.sub.100 =0.5171F                                             R.sub.101 =∞                                                         26           T.sub.101 =0.5171F                                                                             ND.sub.101 =1.523                                                                       ν.sub.101 =58.57                          R.sub.102 =-0.9486F                                                                            S.sub.101 =0.0103F                                             R.sub.103 =∞                                                         27           T.sub.102 =0.5688F                                                                             ND.sub.102 =1.523                                                                       ν.sub.102 =58.57                          R.sub.104 =-1.15669F                                                                           S.sub.102 =0.0103F                                             R.sub.105 =1.61446F                                                        28           T.sub.103 =0.5688F                                                                             ND.sub.103 =1.523                                                                       ν.sub.103 =58.57                          R.sub.106 =-12.7564F                                                                           S.sub.103 =1.0910F(4X)                                                           2.6422F(10X)                                                                   5.1241F(100X)                                            __________________________________________________________________________

wherein the coefficients of asphericity for R₄ are: k = -0.99341 d = -0.50246 × 10⁻⁴ e = -0.43451 × 10⁻⁵ f = 0.11169 × 10⁻⁶ g = -0.57450 × 10⁻⁹ wherein the coefficients of asphericity for R₅ are: d = -0.59858 × 10⁻⁴ e = -0.44852 × 10⁻⁵ f = 0.10981 × 10⁻⁶ g = -0.60834 × 10⁻⁹ k = -0.98417and asphericity Z of the respective lenses R₄ and R₅ for any given value of x and y is defined by the equation

    Z = cp.sup.2 / [1 + √1 - (k + 1)c.sup.2 p.sup.2 ] +dp.sup.4 + ep.sup.6 + fp.sup.8 + gp.sup.10

when c = 1/R₄ or 1/R₅ respectively and p² = x² + y².
 9. The illumination system according to claim 8 wherein F is 9.67mm. 